It is known that the practice of printing on a ribbon labels designed to be applied to successive containers, the ribbon being wound in the form of a roll and being provided with a film of glue at the face designed to adhere to the containers to be labeled, is currently widespread: one thus speaks of pre-pasted labels.
Labeling machines that work on pre-pasted labels provide, according to a usual embodiment, for the presence of a rotating carousel provided with pans for supporting the individual containers to be labeled and with a drum which cuts the ribbon in order to separate each individual label and transfer it onto a container, and said machines are often inserted in packaging lines which for example comprise upstream a filling machine and a capping machine.
Due to a malfunction of one of the upstream machines, it may happen that a container is missing in the plurality that reaches the labeling machine at high speed, and therefore the pan that should have accommodated the missing container remains empty.
The packaging line does not stop and accordingly malfunctions on the labeling machine occur.